Pablo Sandoval, the Red Sox' $17 million backup, is now out for the season with a shoulder injury after just six at-bats

The Boston Red Sox announced on Monday that third-baseman Pablo Sandoval will undergo shoulder surgery after receiving a second opinion on the matter from Dr. James Andrews. A later report from ESPN added that Sandoval is expected to miss the remainder of the season.

Red Sox officials deferred additional comment until after Andrews performs the procedure and declined to offer an updated diagnosis of an injury that had previously been classified as a "strain" or a timetable for Sandoval's recovery. A source told ESPN's Marly Rivera that Sandoval is expected to miss the rest of this season.

Sandoval, who signed a five-year, $95 million contract before the start of last season and currently makes $17 million annually, appeared in just six at-bats this season.